The present invention refers to a method and a machine for the production of reinforcement and Dowel side frames for concrete, from wire or rod or other material of prismatic cross section.
In order to assist in understanding the field of the invention, several representative products that may be delivered by the machine, according to the present invention, are presented in FIGS. 1A-1D. As shown there, the products are characterized by two parallel wire rods and by appropriately formed wire frames, which are welded transversely on specific points on the two parallel wires, in order to create a uniform and rigid at one direction side frame. The transversal wire frames may maintain the same geometry FIG. 1A, FIG. 1B or may vary, by alternating frames of two different geometries FIG. 1C. The product may be characterized by the distance of the two longitudinal wires (b1), by the step of the transversal frame (a1), by the distance of two consecutive transversal frames, measured on the points where their sides meet the longitudinal wires (a2), and the lengths of the transversal wire sides (b2). In the case of alternating transversal frames of two different geometries, the product may be characterized further by the proportion of wire length on each side of the transversal frame with respect to the formation axis (b3).
These products are typically used as reinforcement for concrete as well as in the composition of beams, columns and other construction made of reinforced concrete FIG. 1D. They may also be employed in the construction of buildings, roads and bridges, as well as in support beams for the manufacturing of metal constructions and metal shelters.
The referenced product is manufactured mainly semi-automatically. The transversal parts of the product are manufactured by a bending machine or by a press. The already formed pieces are transferred and placed on the longitudinal wires at specific locations, where they are welded either through electrodes (resistance welding) or through soldering. The disadvantages of the semi-automated manufacturing mode are the difficulty in maintaining the proper product geometry, the not-very consistent welding quality, and the high production cost.
The automated manufacturing was typically achieved with the following two methods. In the first method, the transversal wire frame is formed at an automatic bending machine and then it is transferred, through a robotic system, at the proper location, where it is welded with electrodes (resistance welding). In the second method, the transversal frame is manufactured by a press, and then, through a transfer mechanism, it is placed at the proper location, where it is welded with resistance welding.
The transfer mechanism of the already formed transversal frame constitutes the main disadvantage of the automated production methods, since the transfer mechanism makes the overall machine operation very complicated and expensive. Furthermore, the wire undergoes elastic deformation (recuperation), resulting in changes in the final product geometry and various inaccuracies during the transverse frame transfer.